Section III. PRINCIPLES OF OPERATION
THEORY OF OPERATION. (Refer to Figure 1-3).
Air Compressor Assembly.
The control panel holds (1) gauges, switches, and buttons necessary to operate and monitor the lube
unit. For night missions, panel lamps (2) are included.
A run/stop toggle switch (3) prepares the unit to be started. Pushing the engine start button (4) opens the
solenoid and allows the starter to receive power from the batteries. The starter cranks the diesel engine
The diesel engine (5) turns the alternator (6) which recharges the batteries. The engine also turns the air
compressor (7) which generates and sends compressed air to the air-receiver tank (8).
A system of valves, controls, and devices regulate air compression and ensure safe operating conditions.
A spring-loaded pressure relief valve (9) "pops off' and relieves tank pressure if it exceeds 200 psi,
preventing serious safety problems A ball valve (10) shuts off air to all lubricant pumps An adjustable
pressure-actuated mechanical control/automatic idle control (11) maintains air pressure between 140 psig
and 175 psig and reduces engine speed to recommended idle speed during the compressor unload
A spring-loaded interstage pressure relief valve (12) protects the low pressure cylinder of the air
compressor if the high pressure cylinder fails. A shut-off valve (13) prevents air from entering the air-
receiver tank (8). An automatic unloading device (14) prevents the engine from starting against either
tank pressure or compression in air compressor cylinders. A condensate removal valve (15) drains the
air-receiver tank (8) of moisture and air. A clutch handle (16) engages the clutch and compressor drive
belts, thus allowing air compressor to start working.
Lube Tank Assembly.
The engine-oil, grease, and gear-lube pumps (17) pump lubricant from the lube tank assembly (18) and out
through lubricant hoses (19). Each pump is driven by compressed air that is generated by the air compressor (7).
The lube tank assembly (18) is divided into three compartments: one for engine-oil, one for grease, and one for
Reel Cabinet Assembly.
Lubricant hoses are fitted with meters (20) for precisely adjusting the desired amount of lubricant.
Reels (21) provide a convenient way to store and retrieve hoses in mission situations.
The large drawer (22) houses two batteries mentioned earlier. The two smaller drawers (23) house
accessories needed for missions.
The heater assembly (24) operates off of the batteries and circulates hot air to the diesel engine (5), lube tank
(18), and batteries. The winterization assembly should be used for starting and operating the unit in cold weather.
The trailer assembly serves as a platform for the lube unit and allows towing of the unit from place to place.